1. Field of the Invention
The invention relates to a control device for an extracting unit in the face of a mine.
2. Description of Related Art
A control of this type is generally known.
However, the prior art suffers from the problem that the main valves and the pilot valves can be subject to inner leakage; in particular, in the presence of high pressures of 450 bars that occur. Due to the high energies of leakage flows, they cause damage to the main valves and/or pilot valves rendering them inoperable; in addition, a drop of hydraulically supported loads results.
Consequently, attempts are being made for detecting leaks early. However, this is a difficult feat in cases of inner leaks between main pressure and/or main return lines and return pressure and/or return lines. Attempts to detect such leaks by means of sound measurements have been unsuccessful to date, because it is not possible to distinguish permissible noises, in particular flow noises, from impermissible flow noises.
Therefore, it is the object of the present invention to be able to detect leaks at any time involving only minimal complexity in terms of devices and labor, even in existing systems while said systems are in operation.